OEM. Original Equipment Manufacturer. That's industry gab for 'ghost writers', the anonymous subcontractors who fabricate sub assemblies or complete product without formal credit because their clients attach their own brand label instead. This sets the stage for Hannes Frick, president of Austria's WLM loudspeaker design house. Frick is a tube man but not tube designer. Until now, he always had to rely on other people's electronics to assemble systems for trade shows and customers. But as word spread on Sasa Cokic, head designer at Trafomatic Audio of Mladenovac/Serbia, Mr. Frick approached him with a commission. He wanted a 35-watt valve amplifier which would drive his WLM speakers to perfection - but not prospective owners into hock. Unfairly or not, Frick's standards were educated by Almarro, Manley Labs and E.A.R. Could Trafomatic design and build an amplifier he could be proud to affix the WLM badge to?

Hannes adores EL84s and 6C33Cs in single-ended circuits. But he wanted more power to cover all WLM speaker scenarios. And he wanted equivalent sonics, to hell with reasonable. Shockingly, Sasa proposed the seemingly mundane. EL34s in push/pull. Hannes wasn't moved. Sasa persisted. Hannes shrugged shoulders. He had nothing to lose. He'd simply say no and move on. The onus thus was on the Serbian transformer specialist. Send dynamite. Then Frick performed due diligence. Among others, he compared Cokic's test sample to 9000 euros worth of sterling Russian valve kit compliments of his upscale Italian importer; to his own familiar tube gear inventory; and to big American transistors selling for $6000. Sasa's prototype quickly had his vote.

Alternate concept with split fascia

"The Warsaw hifi show this year once again was a big success, this time with the La Scala. Once again we ran two rooms. I premiered the Sonata with the La Scala monitor and Basic Duo subwoofer in mine. Martin Schützenauer ran the La Scala with the Duo 18 and a big Cary Audio combo in his. Sasa's integrated ran circles around the expensive Cary suite with 6SN7-driven KT88 pairs. This was great fun particularly because it happened under public scrutiny with the most varied of attendee feedback. It really drove home just how accomplished Sasa is at his craft. The Sonata, on all fronts, will become a destination piece of exclusive tube audio. I can hardly wait until we're in full production. Sasa signed up for WLM distribution in Serbia by the way. This might tell you just how fast this collaboration has grown beyond the usual OEM anonymity."

The original prototype I heard in Sasa's home during my RoadTour Serbia visit and which eventually made its way to the critical Austrian audition in Sülz

Admittedly, globally competitive fit'n'finish are challenging to achieve in Serbia. Enter WLM's expertise in fine woodworking. Trafomatic would handle all circuit design, sub assemblies and transformer manufacture. WLM would craft the outer enclosure from Indian Macassar Ebony and outsource the engraved stainless steel front and hole-pattern top panel from their regular local machine shop. This split labor would openly reflect in a 'made in Europe' sticker of origin. Above are early concept renderings which WLM shared with us to document the Sonata's birthing cycle. These drawings make for an unusual behind-the-scenes glimpse of hifi manufacture.

First stainless steel top and front plates from WLM's workshop

Let's backtrack on the business model for a moment and its implications for an audio review magazine. Frick had earlier this year announced a collaboration with Vinnie Rossi of Red Wine Audio. The latter became the US importer for WLM while Frick picked up the RWA tab for Austria. For us, this opened the doors to oft-requested system assessments. To be viable, those must rely on specific combinations of various makers' products being sold as such. Enter our Red Wine Audio Isabella review. Vinnie Rossi had strategically asked me to hold on to his loaner and the matching Signature 30.2 until WLM could dispatch a La Scala tower from their second production run (the first 200 pairs had quickly sold out). This would facilitate a follow-up to Ralph Werner's La Scala test in the context of a laptop, Isabella, 30.2, La Scala chain such as both Red Wine Audio and WLM are promoting and packaging now.

Sasa's personal La Scalas provide a WLM reference in Mladenovac

Next Hannes Frick requested I hang on to the La Scalas until he could dispatch a production Sonata. This returns us to the beginning and this review. Needless to say, sources and cables remain variables. We're merely reporting sonic impressions on packaged systems from manufacturers who've begun to collaborate openly beyond mere lip-service endorsements. To reacquaint yourself with WLM's La Scala, Ralph's review really nailed it. Our focus today is the Sonata. It's the unexpected new player that means to compete in the big league. We'll wrap with a 'system' commentary on the Sonata + La Scala combo. First, Sasa Cokic will run us through the vital stats on his circuit which he believes is one of his best designs yet.

"We have the Sonata and Sonata Signature. The latter adds remote control, a double C-core output transformer, a bigger C-core choke (10H instead of 3), Jensen paper-in-oil capacitors and Mullard-branded New Sensor EL34s. This increases resolution and dynamics and extends response. As is true for all tube amps, transformer quality is paramount. For the Sonata platform, I designed an output transformer that's not exactly common for push/pull applications but significantly improves sonics by minimizing effects from asymmetries that arise with tube mismatches, uneven aging and such. I didn't invent this. I simply know how to do it properly. Because we make all our own transformers, we can prototype extensively and implement small adjustments on the fly that elude even amp designers who work with very reputable magnetics vendors. There's a limit to what those relationships can sustain and finesse. Circuit designers without personal winding experience don't know what to specify exactly or what's even possible. With the Sonata, its very complex output transformer borrows tricks from single-ended designs but optimizes cathode feedback and uses a very complex combination of discrete coils and sections.

"Both input and driver tubes are ECC82/12AU7s and total circuit gain input to output is 27dB. Input sensitivity is 0.6Vref, input impedance 100k, cathode feedback 10dB and output impedance 4/8 ohms. Frequency response for the Sonata is 10Hz flat to 58kHz at -3dB, the Signature version extends the minus 3dB down point in the treble to 82kHz. For the Sonata, we'll provide current production Slovakian JJ tubes. For the Signature, Hannes might offer certain NOS driver tubes. That will depend on availability and customer requests. The Sonata is our proof of concept that it doesn't take exotic valves or uncommon circuits to get superior sound. What matters is circuit integrity and superior transformer craft. The Sonata Signature gets the bigger parts budget and fully maximizes what the platform is capable of."

Added Hannes Frick: "We've worked hard to establish WLM as a quality brand. Expanding into select electronics is the sort of move competitors expect to backfire. After all, others have tried without much success. The Sonata project is different. Trafomatic has already proven solid competence in the market and their transformer craft is truly advanced. Rather than adopting a forthcoming Trafomatic model whose power specs would match our needs, we simply commissioned one. By adding our own cosmetics and moving final assembly in-house, we made it ours exclusively. Our business partners abroad continue to deal directly with us and we're not pushing a new brand. We're just offering one very special integrated solution that's priced to match our La Scala and Diva range and was literally conceived to be their perfect sonic mate. Particularly those dealers who've shied away from tubes because their price limit would have dictated Chinese; or because they didn't have room or the need for a deep line... those dealers can now offer a superior example of the art without reshuffling or defocusing their lineup. Customers meanwhile know that WLM stands behind this product. We offer stability and confidence you might not get from affordable offshore products. So we think it's a real win/win/win - for WLM, for Trafomatic Audio and for our clients."

Vinnie Rossi then made comments which took the concept to the next level: "Hannes sent me some pictures of the Sonata metal work in action. It's looking really good. Ideally, there would be a Sonata power amp as well and even Sonata monoblocks. I'm open to distributing them here in North America. There are those who will never buy RWA amps because they aren't tubed. With the Isabella, this would become an all tube system and the DAC and tube preamp will be SLA battery power. The philosophy here is a warm, rich and analog sounding DAC and preamp with battery power for the delicate line-level signal. Then feed this into the Sonata EL-34 for all-tube greatness!"

The Sonata concept had struck a chord well before first production units rolled off the line. Vinnie was inspired to go farther: "I know that RWA's upscale performance now needs more cosmetic eye candy. The Isabella would be the perfect piece to start with a cosmetic makeover. Perhaps Hannes would agree to craft us a Sonata-style enclosure? Since the Sonata will be larger than my preamp, if we use a matching enclosure for the Isabella, there would be more room inside for more options (perhaps even that RWA phonostage) and larger batteries for longer play time between charges. With the WLM woodshop and a machine shop local to them, I'm sure we can come out with some really nice looking gear in the future. Hannes has a lot of drive and enthusiasm and it is a pleasure teaming up with someone like that."

What began as a one-model commission between two manufacturers quickly snow-balled to involve threeand a number of models. As the Sting song puts it, synchronicity. Hannes promptly drafted a sketch for the stereo/mono Sonata amplifiers.

"The Sonata enclosure is crafted from massive high-density Plywood with a Macassar veneer. To protect the rounded-over upper and lower edges, we've bonded multiple veneer layers to achieve extra thickness. For the Signature version, I want to avoid an IR sensor on the front so we'll go for a stealth installation on a cheek where it will be mostly hidden by the dark veneer pattern. Our master craftsman Thomas Gröfler is responsible for the stunning Sonata woodwork."

Sonata main circuit board

"We are formally introducing the Sonata at the 2009 CES. That'll be merely the beginning of WLM's collaboration with Trafomatic. Sasa is hard at work conceptualizing future models in our emerging line of fine valve equipment. I predict you'll be seeing some of them throughout the year. Alas, we're not in a rush. Being Austrians, our motto is pedantic but perfect. Only when Sasa, his partner Misha, my partner Martin and I agree that the next model is fully mature will we introduce it. With the €2,990 Sonata, we already have the perfect solution for our Diva and La Scala models. Those are our bestselling and most affordable speakers and the Sonata was deliberately priced to match."